[PATCH] classes: add devupstream class

[PATCH] classes: add devupstream class

[Ross Burton]

This class lets you use BBCLASSEXTEND to add a variant of the recipe that
fetches from an alternative URI (such as git:) instead of a tarball.

For example:

 BBCLASSEXTEND = "devupstream:target"
 SRC_URI_class-devupstream = "git://git.example.com/example"
 SRCREV_class-devupstream = "abcd1234"

This variant will have DEFAULT_PREFERENCE set to -1 so it needs to be selected
to be used, and any development-specific tweaks can be done with the
class-devupstream override, for example:

 DEPENDS_append_class-devupstream = " gperf-native"

 do_configure_prepend_class-devupstream() {
    touch ${S}/README
 }

It currently only supports creating a development variant of the target recipe,
not native or nativesdk.  The BBCLASSEXTEND syntax (devupstream:target) was
chosen so that support for native and nativesdk can be added at a later date.

Support for other version control systems such as subversion is limited, as
bitbake's automatic fetch dependencies on for example subversion-native are not
generated.

[ YOCTO #10215 ]

Signed-off-by: Ross Burton <ross.burton@intel.com>
---
 meta/classes/devupstream.bbclass | 48 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 meta/classes/devupstream.bbclass

diff --git a/meta/classes/devupstream.bbclass b/meta/classes/devupstream.bbclass
new file mode 100644
index 0000000..7d4113f
--- /dev/null
+++ b/meta/classes/devupstream.bbclass
@@ -0,0 +1,48 @@
+# Class for use in BBCLASSEXTEND to make it easier to have a single recipe that
+# can build both stable tarballs and snapshots from upstream source
+# repoistories.
+#
+# Usage:
+# BBCLASSEXTEND = "devupstream:target"
+# SRC_URI_class-devupstream = "git://git.example.com/example"
+# SRCREV_class-devupstream = "abcdef"
+#
+# If the first entry in SRC_URI is a git: URL then S is rewritten to
+# WORKDIR/git.
+#
+# There are a few caveats that remain to be solved:
+# - You can't build native or nativesdk recipes using for example
+#   devupstream:native, you can only build target recipes.
+# - If the fetcher requires native tools (such as subversion-native) then
+#   bitbake won't be able to add them automatically.
+
+CLASSOVERRIDE .= ":class-devupstream"
+
+python devupstream_virtclass_handler () {
+    # Do nothing if this is inherited, as it's for BBCLASSEXTEND
+    if "devupstream" not in (d.getVar('BBCLASSEXTEND') or ""):
+        bb.error("Don't inherit devupstream, use BBCLASSEXTEND")
+        return
+
+    variant = d.getVar("BBEXTENDVARIANT")
+    if variant not in ("target"):
+        bb.error("Pass the variant when using devupstream, for example devupstream:target")
+        return
+
+    # Develpment releases are never preferred by default
+    d.setVar("DEFAULT_PREFERENCE", "-1")
+
+    uri = bb.fetch2.URI(d.getVar("SRC_URI").split()[0])
+
+    if uri.scheme == "git":
+        d.setVar("S", "${WORKDIR}/git")
+
+    # Modify the PV if the recipe hasn't already overridden it
+    pv = d.getVar("PV")
+    proto_marker = "+" + uri.scheme
+    if proto_marker not in pv:
+        d.setVar("PV", pv + proto_marker + "${SRCPV}")
+}
+
+addhandler devupstream_virtclass_handler
+devupstream_virtclass_handler[eventmask] = "bb.event.RecipePreFinalise"
-- 
2.8.1